Plug switch



March 3 1931.

J. H. KLIEGLM PLUG SWITCH" Filed Jan. 8, 1929 parted Mar-. 3, 1931 UNITED STATES PATENT OFFICE JOHN E. KLIIGL, OI NEW YORK, N. Y., .ASSIGIIOB TO KLIEGL BROS. UNIVERSAL ELEC- TRIO STAGE LIGHTING 00., INC., 01 raw YORK, N. 'Y., .A CORPORATION OF NEW YORK Imusswrrcn Application filed January 8, 1929. Serial No. 831,024.

This invention pertains to plug switches I for electric cables, and has particular reference to the means for interlocking the separable parts of the device to prevent inadvertent or accidental separation of the parts in ing pair of terminals in the other half of the device when the two halves are brought together into operative relationship. It is customary to connect the terminals of the line cable to tubular sockets, and of the load cable to projecting plugs adapted to enter the line soc :ets so as to complete circuits therethrough. i

In the endeavor to design the device so-as to permit ready separation in response to a pull by the operator, and'yet prevent inadvertent separation while otherwise handling the switch or cables, the plugs have been made to fit snugly into the sockets either by turning them to proper diameter or by providing for spring contact between plug and socket. Such'expedients, however, have not worked well. In service the carefully fitted plugs, after a few separations, become too loose to function properly as a means for holding the socket arrangements are objectionab plug together, and the spring-like plug-madcause they a d complications to and im air the efiiciency of the parts of the switch w ich arecalled upon to transmit current.

Attempts have also been made to provide auxiliary devices aside from thexplugs and sockets to accomplish the desir purpose, but so far as I am aware none has been satisfactory. They are either clumsy, or ineifectige, or expensive, or otherwise objectiona 1c.

The object of the present invention to provide a plug which is effective in'operation even after long use, attractive in appearance, and of very low cost of manufacture.

Further and other objects will be apparen from the accompanying s cification, and

from the drawings which y way of illustration showwhatis'now considered the preferred form of the invention.

1 is a perspective view of the device. Fig. 2 is a front view of the device, with its arts separated and partly broken away. 1g. 3 is a cross-section on the line 33 of B13 ig. 1.

i 4 is a view of a i late on the line Hi): Fig.3. gr p P Fig. 5 is a perspective view of the locking element. y

The device comprises two substantially similar body members and 12, both made of rubber bakelite, or similar insulating material. B ach member provides a groove 14 to accommodate the end of an insulated cable such as line cable 16 and load cable 18. Each cable is clamped in place by a locking plate 20, secured to its corresponding body membar by screws 22, and provided with projectmg corrugatio'ns 24 so placed as to enter groove 14 and enga the insulation of the cable to take any pu l on the cable.

The end of each wire 26 of line cable 16 is attached by a screw 28 to a tubular metallic socket 30 imbedded in member 10. In like manner wires 32 of load cable 18 are connected to a pair of cylindrical plugs 34 having projecting ends 36 of proper diameter to enter sockets 30 and make electrical contact therewith when the two body members of the device are placed together as in Figs. 1 and 3. Terminal plugs 36 are slotted and their ends slightly spread apart to insure close rcsilient contact with sockets 30.

' The switch as described above can function as a device for operatively making or breaking electrical connections between cables 16 and 18, but the two members are liable to come apart in service because they are held together only'by the resiliency of plugs 36. To avoid accidentalseparation I provide an additional impositive locking means in the form of a spring clip 40 formed from a flat strip of spring metal, preferably bronze. Thefstrip is bent upon itself to form at the middle of its length a hollow cylindrical portion 42, while the free ends are formed in the sh ape of hollow semi-cylinders 44- so disposed as to form a split cylinder when the free ends ly equal to the thickness of members 10 and 12. Clip 40 is securely anchored in asocket provided in member 12. The socket comprises a drilled portion to tightly receive cylinder 42, and a slot permitting the ends of the clip to extend freely beyond mating face 46 of member 12 in a direction generally parallel to plugs 36. Member 10 is provided with a socket of the same general shape as the socket in member 12, with a drilled portion 48 connected by a slot 50 to mating face 52.

Slot 50 is of such width that free ends 44 of the spring clip may be forced by the operator through the slot into space 48 while plugs 36 are entering sockets 30." While passing through the slot, ends 44 are necessarily slightly deformed by the walls of the slot, which means that they must be deformed again to the same extent in order to pass out of slot 50 when it is desired to break the electrical connection between cables 16 and 18. Clip 40, therefore, provides a simple, cheap, thoroughly practical means for preventing inadvertent separation of the plug, yet permitting separation by the operator when necessary.

It is to be understood that the invention is not limited to the specific embodiment herein described but may be used in other forms without departure from its spirit as defined by the following claims.

I claim 1. In a plug switch of the kind described, in combination, a first body member of insulating material in which a pair of terminal sockets are imbedded, a second body member of insulating material provided with a pair of terminal plugs each adapted to enter and form contact with one of said sockets when said first and second body members are brought into operative relationship, a socket formed in the body of said first member between its terminals, and a spring clip imbedded firmly in the body of said second member and projecting therefrom and ada ted to enter and resiliently engage said soc et in said first member when said first and second members are brought into operative relationship, thereby providing an impositive lock between said members. I

2. The invention set forth in claim 1 in -which said clip comprises a strip of sprin metal folded on itself to form at the middle of its length a hollow cylindrical portion and having its free ends formed in the shape of hollow semi-cylinders so disposed as to form another hollow cylinder when the free ends are pressed together, one of said cylindrical portions being adapted for imbedding in said second member and the other cylinder portion being adapted to be forced into the socket in the first member to provide an impositive lock therewith.

3. The invention set forth in claim 1 in which the projecting portion of said clip comprises a hollow cylinder, and means for supporting said cylinderwhereby it'will enter and resiliently engage the socket in said first member for the purpose set forth.

4. The invention set forth in claim 1 in which the projecting ortion of said clip comprises a hollow cylin er, and means for supporting said cylinder whereby it will enter and resiliently engage the socket in said first 

